Fluid pressure remote control system



' June 27, 1944.

Q. H. CARLTON 2,352,470

FLUID PRESSURE REMOTE CONTROL-SYSTEM-J l June 27, 1944. Q, H CARLTQN 2,352,470'

'FLUIDPRESSURE REMOTE CONTROL SYSTEM Filed June 26, 1942' 5 sheets-sheet 2 Fly 4, 22

146 `O; y 110 1415 IMI/Enna Q-H-CIRLToY By: la 1,9m

June 27,1944. Q. CARLTON 2,352,470

FLUID PRESSURE REMOTE CONTROL SYSTEM Filed June 2S, 14942 l3 sheets-Sheet 5 @3 4 llaa. 44 ma lo .180177 426 Fgzz NWI; I8!- A y.178 zu17/'.9154 'J62`/ v 136" l -187 183 Q. H.CAR|.TON

Ill/YE# raft l Patented June 27, 1944 FLUID PRESSURE REMOTE CONTROL SYSTEM Quintin Healey Carlton, Leamington Spa, England, assignor to AutomotivefProducts Company Limited, Leamington Spa, England Application June 26, 1942 Serial No. 448,640 In Great Britain March 24, 1941 7 Claims. (o1. 121-38) This invention relates to uid pressure remote control systems.

Itis an object of the invention to provide an im-- proved method and means for causing the piston necting the said piston with a change-over valve adapted to connect a supply of pressure liquid with one or other working space of the motor, the position of the piston at change-over being arranged to coincide with the said predetermined setting.

According to a further aspect of the invention, a motor unit for a fluid pressure remote control system comprises a movable member urged in opposite directions by uid pressure in one or other of a pair of working spaces, interchangeable flow and return pipe lines leading to said spaces, and

a change-over valve which, when fed with pres- :x

sure iiuid, conducts it to either one oi said working spaces, depending. upon the state of the valve, the latter being connected operatively with the movable' member so that, by changing over when the said member reaches a predetermined position in its stroke, the valve serves to maintain the movable member in the said predetermined position as long as said valve is fed with pressure uid.

Preferably, a pair of fluid actuated cut-off valve devices are provided, these being respectively interposed between each branch of the changeover valve and the corresponding working space of the motor unit. A movable member may comprise a doub-le-acting piston arranged to slide within a motor cylinder. Further,v the changeover valve may be provided with a rocker which is connected with the movable member conveniently by a lost-motion device, which latter may be operative on both sides of the predetermined position at which the change-over valve is changed over. The lost-motion device may comprise a rocker having a substantially V-shaped cam surface which is engaged by a member connected with the movable member of the motor unit, said change-over valve comprising a pair of the ends of its stroke consists in operatively convalves each having a push rod by which it is urged off its seat by the movable member of the motor unit. If desired, each of the cut-oir valve devices may comprise apartition piston disposed within a bore and arranged to be forced in one direction by pressure uid supplied through the corresponding main pipe line, and in the other direction by fluid supplied through the auxiliary pipe line, the resulting movement of the partition-piston serving to connect the said working space of the motor unit with the pipe line through which the fluid is being supplied, and to isolate said Working space from the other of the above-mentioned two pipe lines.

According to a further aspect of the invention, there is provided a liquid pressure remote control system having a motor unit as above described, the arrangement being such that a control valve device, through which pressure liquid is fed to either one of the main pipe lines or to the auxiliary pipe line, is provided with a time-controlled valve device which causes pressure liquid to be fed from the source for only a predetermined and limited period each time the setting of the control valve device is changed. Preferably, the time-controlled valve device comprises a piston valve member having its movement governed by a dash-pot device, said piston valve member being moved against the action of a spring, by a cam which is operatively connected with means for actuating a selectorvalve portion of the control valvedevice.

AThe invention is illustrated by way of example in the accompanying diagrammatic drawings, in which: y. Q

Figure 1 shows one form of remote control system which is operated by-liquid pressure and is adapted to control the change-speed gear box and the engine of a boat;

Figure 2 is a sectional elevation of a modied form of control `valve device, certain associated parts of the system being-shown together with the relevant pipe connections;

Figure 3 is a fragmentary sectionalV elevation taken on the line 3-3 of Figure 2;

Figure 4 is a similar view taken on the line 4 4 of Figure 2;

Figure 5 isa sectional elevationof a .modified form of a motor cylinder unit and associated valve y mechanism;

Figure 'I is a sectional diagram of one of the resistance valves shown in Figure 6; and

Figure 8 is a side elevation of a modified form of cam for the time-controlled valve plunger.

The system shown in Figure 1 comprises briefly a control valve device A having an operating handle I which is adapted to move in either direction from the neutral position, which is indicated at |01. A motor driven pump B receives liquid from a reservoir C and delivers it under pressure to an accumulator D incorporating the usual cut-out valve, the pressure liquid being fed as required from the accumulator to a double-acting motor unit E, depending upon the action of the control valve device A. Incorporated in the latter is a master cylinder device F, which is also actuated by the handle Ill and is adapted to control hydraulically a throttle actuating motor cylinder -G for regulating the speed of the engine (not shown), :a hydraulic adjusting device H being lprovided Yfor initially setting the throttle'so as to give the desired minimum Iengine speed. j

'The control valve device A has a :body I I 'formed -with four mutually `parallel 'bores I2, I3,

seen; the various operating positions of the :han-

dle I0, as indicated by the legends Ahead, NeutraLfAstern Slow and Fastj are lcorrespondingly turned into the vplane of `the drawings.

Means suchassprings (not shown) Yare provided to @maintain the plungers I6, I`1 and I9 in contact with `the cams y2l), 21 and 23,'respectively, while. in ,the case off the plunger I18, the

lower end of .the latter is enlarged to form a dash-potl piston 25 which slides in a substantially liquid-tight manner within qan enlarged part of lthe bore. III and is urged upwards by a coiled compression spring '26. The piston 25 has anonreturn ball .valve 21 which opens during downr ward movement of the piston 25 'but'closes when the piston tends to move upwards on account of 'the spring 26, thus delaying the lupwardmove- .ment ofrsaid vpistonl25, for `the liquid ,trapped above lsaid piston can .only escape at a slow 'rate through a constriction indicated at ,28. The space below the piston 25 is in permanent `communication with the reservoir C by a connection l29 leading into a pipe 30 joining the reservoir C tothe inlet 3| of the pump Bj; the connection 29 also leads to a port 32 vin the bore 'I4 as shown. The delivery connection 33 of the Dump B `leads to the accumulator `D and the voutlet connection 34 from said accumulator D leads to yanother port 35 in the bore I4. A third port v36 in this vbore leads to `a port 31Ain the bore I3, whichjport is at .al1 times in communication with an axial passage 38 leading axially through the plunger I1 .to an annular groove 39 formed therein. This annular groove is adapted to register with any one of three passages 40, 4I and 42, depending .upon the position of the plunger AI1; these passages Llead into the bore I2 at spaced positions and are also in Vpermanent communication with E. These comprise a pair of main pipe lines 43 and 44 connected with the passages 40 and 42, respectively, and an auxiliary pipe line 45 which is connected with the passage 4I. The plunger member I6 has a pair of wide annular grooves 46 and 41 which are permanently connected with the reservoir C by way of a pipe 48 and a branched connection V49. It lwill be noted that a circumferential land D upon the plunger member I6 is adapted to lclose either one of the passages IIB-42,

' 1depending uponthe position of the plunger I6, but

three pipe lines leading to the motor cylinder unit the other two of said passages are connected with `the reservoir C. As the cams 20 and 2I are identical in shape, the plungers I5 and I1 ,move in .unison andthe land 5i) therefore closes that particular passage 40-42 which is in communication With the annular groove 39.

'-Ihe motor cylinder unit E comprises a body 5I formed with a cylinder bore 52 within which a motor piston 53 is slidably mounted. A piston rod 54 extends :through both end walls 55 and 56 of the cylinder, its right-hand end 51 being connected with the usual change-speed lever or equivalent (not shown) of the transmission gear Ywhile the left-hand end 58 is provided Awith a projecting pin 59 engaging within a rocker 6D inthe lform of a substantially rectangular-frame. This rocker 6l] is pivoted 4at v6I to a projection 62 formed upon the Ibody 5I, the upper surface 63 of said rocker adapted to lift either -oueof a .pair `of push rods=64 .and .65, depending upon `the direction of .angular movement of said rocker. The push rods 64 and 65 are adapted to c'o-operate `with ball Valves 6'6 and 61, respectively, so as -to lift `either one of said ball valves against `the action of a corresponding spring `68 or 69 depending upon the .direction in which the rocker 60 is moved angularly. Thespaces above the ball valves '66 and 61 are connected together by a handend of the cylinder bore 52 to a position adjacent the left-hand end of the bore'16, while a passage 19 connected with the main pipe line '43 Venters the bore '16 at a position tothe right of the passage 18. VThus when liquid is fed through the passage 1I it displaces the partition piston 15 to the right unti1 the passage 18 is uncovered, but such movementis limited -by a stem 80, thus ensuring that while passage 18 is connected with vthe passage 1I, said passage 18 is isolated from the `passage 19. Similarly when the partition piston -"l5 is in its normal position, as shown, the passages 19 and 13 are connected together but are isolated from passage 1I. The :cut-ofi valve device 14 is of similar construction and has ya partition piston 8l which, in the position shownfenables pressure liquid t0 ow from the main pipe line A44 to passage 82 leading to the `right-hand end of the cylinder bore 52. On the 4other hand, when pressure liquid is supplied through the passage 13 from the auxiliary pipe line Y45, the partition piston 8l is urged towards the right and permits said liquid to flow into the 4passage 82, Awhich latter is isolated from the main pipe line 44. If-desired, the pin 59 may be ,adjustable on the piston rod 54 to permitadjustment of the intermediate position of the piston '53.

With regard to the throttle controlling means, the bore I of the master cylinder F is connected by a pipe 83 with a working space '84 within the throttle motor cylinder G. The piston of the latter is indicated at 85 and has a piston rod 86 connected with the usual engine throttle or equivalent (not shown), the piston being retracted by a coiled compression spring 81. The retractional movement (i. e. movement towards the left) is, however, limited by a projection 88 upon a stop piston 89 sliding in a liquid-tight manner within the motor cylinder. A liquid space 90 behind the stop piston 89 is connected 'by a pipe 9| with the space 92 at the right-hand end of the hydraulic adjusting device H. The :latter has a piston 93 movable along a cylinder bore 94 by means of a screw 95, so that as the piston 93 is advanced liquid is forced along the rpipe 9| and correspondingly advances the stop piston 89, thus regulating the fully retracted position of the motor piston 85. A port 96 in the cylinder 94 is in communication with the Vreservoir by a connection 91 so that, if necessary, the

liquid within the spaces 90-92 and the pipe 9| can be replenished by withdrawing the piston 93 beyond the port 95.

The system shown in Figure 1 operates as follows. When the handle I0 is in the neutral position, as shown, the plungers I6 and |1 are in their intermediate positions, while the plungers I8 and I9 are fully raised. With the system in a static condition (i. e. after sufcient time has elapsed since the last actuation of the handle I0 for allowingthe plunger |8 to resume its fully raised position) the outlet connection 34 from the accumulator D merely leads into a groove 93 in the plunger I 8, while a similar but wider groove 99 places the port 36 in communication with the port 32 and thus with the reservoir C; as a consequence of this the auxiliary pipe line is in communication with the reservoir. Also the main pipe lines 43 and 44 are both in communication with the reservoir C by way of the grooves 46 and 41, respectively, and the branched passage 49.v When the handle I0 isvmoved, say in an anti-clockwise direction to the position indicated at 99, the initial part of this movement causes a lobe |00 upon the cam 22 to depress the f.

plunger i8 to the maximum extent, this being 's uicient to bring the groove 98 into communication with the port 36, which latter is, of course,

Ythen cut off from the port 32 leading to the reser- `Voir C. When the handle |0 has reached 'the lposition 99, the lobe |00 has passed the top of the plunger I8 so that the'latter is then free to 'return at a slow rate to its uppermost position;

as a result pressure liquid from the accumulator D is fed for a predetermined period (depending upon the size of the constriction 28) to the port 36, after which period said port 36 again becomes connected with the reservoir C.

The movement of the handle I0 to the position 99 causes the plungers I6 and I1 to be depressed by the cams 20 and 2|, the extent of the movepassage 82, andA thence into the right-hand working space |0| of the motor cylinder unit E. ri'his pressure liquid forces the piston 53 towards the left until the end wall 55 is reached and the piston 53 is arrested. The movement of the piston 53 is, of course, transmitted to the piston rod 51 and the latter moves the usual selector lever (not shown) of the Vchange-speed gear box to its ahead position. If the handle I0 is moved beyond the position 99, the arcuate portions |02 and |03 of the cams 20 and 2| slide past the plungers I6 and I1 without changing the positions of these plungers. From the position 99 to the position |04 the handle I0, however, serves to adjust the engine throttle by means of the cam 23 and the plunger I9. That part |05 of the periphery of the cam 23 corresponding to the movement of the handle |0 to the position 99 is ofv constant radius with respect to the axis of the shaft 24, so'that the plunger I9 is not shifted; from the position'99 of the handle |0 to the position |04, however, the curved part |06 (which is shaped in a spiral or involute fashion) engages With the top of the plunger I9, thus progressively depressing the latter so that the liquid, which is rejected from the bore I5, passes to the working space 84 of the motor unit G and advances the motor piston 85 so opening the throttle until maximum speed is reached with the handle I0 inthe position |04. The handle I0 can, of course, be moved backwards and forwards between the positions 99 and |04 as required to control the speed of the engine without having any effect upon the adjustment of the motor cylinder unit E.

The next time the handle I0 is moved back to the neutral position, indicated at |01, thev lobe |00 is forced past the top of the plunger I8, thus depressing the latter, while, at the same time, plungers I6 and |1 are restored to the positions shown in Figure 1. For a brief period, therevfore`(i. e. while the plunger I8 is slowly rising on account of the spring 26) pressure liquid, which is fed from the accumulator D, passes through the port 36, along the passage 38, through the plunger |1 and thence to the passage 4| and the auxiliary pipe line 45. It will be remembered that the previous movement of the handle I0 caused the piston 53 of the motor unit E to be moved to the left and this, of course, caused the pin 59 to tilt the rocker` 60 in a clockwise direction so that it raised the push rod 64 and lifted the ballValve-SB 01T its seating. As pressure liquid is now being fed from the auxiliary pipe line 45, therefore, liquid passes the ball Valve 66, said liquid then ilowing along the passage 1|v and displacing the partition piston 15, lthus enabling'said liquid to flow through the passage 18 to the left-hand working space |08 of the Vmotor unit E. As a consequencethe piston 53 moves to the right, but when it reaches its central position corresponding to'the neutral position of the gear box selector lever, the pin 59 restores'the rocker 60 toits intermediate position' as shown, thus closing the ball valve 66. As a consequence, no further liquid can be supplied through the auxiliary pipe line 45, andwhen the plunger I8 of the control Valve device A regains its uppermost position, said auxiliary pipe line 45 is again placed in communication with the reservoir C. Should the piston 53travel bevyond-its'central position, however, the rocker 60 willbetilted :inthe fo'pposite direction', i; e. anticlockwise; thussforcingl the balltvalve I 61 fof its seatiand permitting suicientliquid -fromlthe `auxiliary pipe line 45 to pass into the right-hand Working space to return (the .piston :.53 bythe requisite amount.

Thefsame sequencefof operations occurs when the handle I0 is moved to the position |09 for bringing the selector lever of the gear box to :its astern'position. During this; movementof the handle I0, a second lobe .H0 upon the .cam 22 ldepresses the `plunger I8, While -the ,plungers IS and Il are allowed to rise until they engage with curved portions I-TH 4and I I2 of constant small radius upon the cams and 2|, respectively. Movement of the handle I0 from the position |09nto the position H3 again serves to adjust the throttle motor `unit G, the curved portion H4 of the cam 23 acting to `depress the plunger I9. Y

The modified construction ofvoontrol valve device A, `shown in Figures 2 to 4, operates in a somewhat similar manner -to 4that ,previously described, but it is adapted for use where it is not desired to instal an accumulator, the pump B having its inlet 3| connected directly with its outlet .33 whenever :it Vis not required to supply pressure liquid for actuating the vmotor -unit E. Also, in the modied arrangement, the functions of the previously described plungers I6 and `IfI are carried fout by a single plunger, indicated lat `H5 in Figure 2. The plunger I9 and -cam 2:3 .are rthe same as before and serve to actuate a throttle motor cylinder unit G, the fully retracted position of which is regulated by a`hydraulic adjusting -device H; the latter is connected with the reservoir C as before.

The time-controlled valve plunger is again in- I dicated at I8, but in this instance it is formed with three axially spaced circumferential grooves H6, H'I and H8, connected permanently together by a longitudinal passage H9. When the plunger I8 is in its fully raised position` these grooves register with three ports |20, |2I and |22, respectively, but `While the plunger is depressed, these ports are isolated from one another. The lower end of the plunger I8 is fitted with a'piston 25 asbefore, having a number of passages 23 adapted to be covered by an annular ilap valve member |24 acting as a non-return valve. The requisite leakage passage to control the upward movement of the plunger I8 is, in this instance, obtained by making the piston 25 a slightly loose iit in the bore.

The plunger H5 has adjacent its upper and lower parts a pair of fairly wide circumferential grooves |25 and |26; between these itis formed with an annular narrow groove |21 which communicates by a longitudinal passage |28 with the space below the plunger I I5. A pair of ports |29 and |30 are connected with the main pipeline V43, while a corresponding pair of `ports |3| and |32 communicate with the other main pipe line 44. On the other side of the bore within which the plunger H5 slides, ports l|33 and |34 are connected bythe passages shown in dotted lines with the ports |20 and |22, as Well as with the reservoir C. Alsofthree spaced ports |35, |36 and |31 are connected together and lead to the auxiliary pipe line v45. The space below the plunger H5 is connected 'by a passage |38 with the port I 2| and is also connected With the outlet 33 of the pump B.

The plunger H5 is actuated by a cam |39 k(see Figure 3) which corresponds in shape to each of the cams 20 and 2|, shown in Figure 1. Instead of bearing directly upon the top of the plunger H5, however, it co-operates'witha roller |40 carried by an arm `|4| which is pivoted at |42, the arm itself being arranged to bear against the plunger H5. In a similar manner, the cam 23 acts upon the plunger I9 through a roller I4`I and rocker |48. The cam 22 (see Figure 4) which actuates the time-controlled valve plunger I8, operates through a roller |43 carried byvan arm |44, said arm being at all times urged upwards by a plunger |45 containing a coiled compression spring |46; by this means the arm |44 is .held free of the plunger I8 and the slow upward movement ofthe latter is therefore not impeded by the arm |44.

The operation of the control valve device shown in Figure 2 is briefly as follows. As in the previous example, whenever the parts of the vcontrol valve device 4are in a static condition (i. e. after suiiicient time has elapsed since the last actuation of the -handle I0 for allowing the plunger I8 to resume its fully raised position) all three of the pipe lines 43, 44 and 45 are connected with the reservoir C. Angular movement of the handle I0 in an anti-clockwise direction is arranged to depress the plunger H5 causing pressure .liquid to be supplied for a `predetermined period to the main pipe line 44. On the other hand, movement of the handle I0 from the neutral position in a clockwise Adirection allows the plunger H5 to rise and thus pressure liquid is fed to the other main pipe line 43. Whenever the handle I0 is returned to the central neutral position, pressure liquid is supplied for a predetermined period to the auxiliary -pipe line 45. In order to achieve these results, the parts co-operate in the following manner. Whenever the plunger I8 is in its fully raised position, the output from the pump B passes through the passage |38 and can return freely to the reservoir C by way of the ports |20 and |22. When, however, the plunger I8 Ais depressed and -while it is returning to its raised position, the ports |20, |2I and |-22 are blocked so that the pump B builds up pressure and the delivery passes through the passage |28 in the plunger H5.

Now assuming that the handle I0 is moved from its neutral position in an anti-clockwise direction so as to depress the plunger H5, the pressure liquid, which is temporarily being xsupplied at working pressure by the pump B, passes through the groove |21 to the port |3| and thence to the main pipe line 44. If the control valve device -is connected to a motor unit similar fin form to that Yshown at E in Figure 1, the admission of pressure liquid to the main pipe line 44 would, of course, move the -piston 53 to the lef-thand end of its stroke. It should be noted that the downward movement of the plunger H5 has caused the groove |26 to pass beyond the port |32, so that the latter is closed. During this action the auxiliary pipe line 45 is maintained Iin communication with the reservoir C as the groove |25 bridges the ports |33 and |35; also said groove |25 is still in communication with 'the pori; |29, thus connecting `the main pipe 'line 43 with the reservoir C.

When the handle I0 is returned to the neutral position, the pressure liquid, whichis delivered by the pump B (while'the plunger I8 is rising), passes from the Vgroove |2'I to the port `|36 and thence on to the auxiliary pipe Vline 45, thus returning the piston 53 of the motor unit E (see Figure 1) y'to its central position. With .the plunger I5 in its mid position, both ofthe main pipe lines k43 and 44 are connected with the res- Vpass back to the reservoir of the system.

ervoir C by way of the grooves |25 and |26, respectively, which, of course, are in register with the ports |33 and |34.

Asthe handle is moved in an anti-clockwise direction to bring the plunger tov its fully raised position, the pressure liquid, which is delivered by the pump B (while the plunger |8 is rising), passes through port with which the groove |21 now registers, thus causing said liquid to be delivered to the main pipe line 43 so that it moves the piston 53 of the motor unit E (see Figure 1) to the right-hand end of its stroke. With the parts in this position, the other main pipe line 44 is connected with the reservoirV by way of the ports V|32 and |34 which are con nected together by the groove |26, while the auxiliary pipe line 45 communicates with the reservoir by way of the port |31 which has been uncovered by the groove |26.

The construction of motor cylinder unit E, which is shown in Figure 5, corresponds largely with the one already described, but it incorporates a modied form of cut-01T valve device. The body 5| is again formed with a bore 52 containing a motor piston 53 and the piston rod 54 of the latter has a pin 59 co-operating with a somewhat triangular rocker 6D pivoted at 6|. Each of the push rods 64 and 65, which co-operate with the rocker 60, is formed with a flange |49 by which it is urged downwards owing to the action of a relatively strong coiled compression spring |50. Each of the ball valve members 66 and 61 is urged on to its seating by a relatively weak coiled compression spring, these being indicated at 68 and 69, respectively. The cut-01T valve devices comprise a pair of vertical bores |5| and |52 lcontaining slidable partition pistons |53 and |54, which are urged downwards by coiled compression springs |55 and |56. A passage |51 connects the lower end of the bore |5| with the space below the ball valve member 66, while, in a similar manner, thev space below the ball valve member 61 is connected with the lower end of the bore |52 by a passage |58. The passage 18, from the left-hand working space |08 whereas when pressure liquid isfed through the auxiliary pipe line 45 it vflows' past whichever of the ball valves 66 or 61 is held o" itsseating and then reaches the appropriate port |59 or |60 by raising vthe corresponding partition pis- In the construction shown in Figure 5, the rocker member 60 comprises a pair of similar plates |66 and |61, which are connected together by bolts |68, spacing members (not shown) being l provided to hold the plates |66 and |61 apart so that the piston rod 54 passes betweenvthem.

The invention is also applicable in cases where it is desired that the motor piston shall be brought automatically to any one'ofa plurality of positions intermediate the ends of its stroke, a

corresponding number of rocker members 6|]I being provided; such an arrangement adapted to have two intermediate positions, is shown in Figure 6. For moving the motor piston to a position indicated at 53a, a rocker member 60a is pivoted 5 valves 66a and 61a.

of the motor cylinder, enters the bore |5| by a of rthe partition pistons is circurnferentially l grooved leaving a pair of axially spaced lands |6| and |62, each of which is madeqslightly narrower in width than the corresponding port |59 or |60. Moreover, the lower land |62 is drilledv parallel to the axis to form a number of passages |63, which latter are normally closed by a light annular plate |64 which` is lifted by a coiled compression spring |65 so as to act as a non-return valve. If, therefore, one of the partition pistons should become jammed in an elevated position, liquid which is pushed out of the cylinder bore 52 by movement of the motor piston 53 can easily displace the annular plate |64 and It Vshould be mentioned that in each case the spring |55 or |56 is sufficiently strong to enablethe downward force exerted upon the partition piston |53 or |54 to develop suicientpressure to open the corresponding ball valve 66 or 61 against at 6|a for co-operation with the pin 59 carried by the piston rod 54; the rocker 60a operates push rods (not shown) in the manner previously described so as to open'one or other of a pair of For moving the motor piston of the second intermediateposition, indicated at 53h, a second rocker member 69h, which is shown in dotted lines for clarity, also` engages with the pin 59 and is pivoted at 6 Ib so as to operate either of a pair of valves 66h or 6111. The spaces below the valves 66a and 66h are connected together and lead to a cut-off valve device 12, which is similar in construction to that shown in Figure 1, while the valves 61a and 61h are similarly connected'with a cut-off valve device 14. The main pipe line 43 is also adapted to supply pressure liquid through cut-off valve device 12 for moving the motor piston to the extreme right-hand end of the cylinder 52, while the other main pipe line 44 acts to move the motor piston to the left-hand end of its stroke. An auxiliary pipe line 45a, through which pressure liquid is fed to move the piston to the position 53a, has a pair of branches |1011 and `|1|a leading throughhydraulically actuated stop valve devices |12a and [13a to corresponding resistance valve `units |14a andv |15a, the outlet connections from which lead to the valves 66a and 61a. In a similar manner a second auxiliary pipe line 4519 corresponding with the piston position 53h feeds through ybranches |196 and |1|b and stop valve devicesA |12b and |13b to resistance valve units |141)` and |1517 to the valves` 66h and-61h respectively. The arrangement and functionof the stop valve devices, which are all similar, andthe resistance valve units will be clear from Figure IQWhi'ch shows as an examplethe stop valve device |121) and the resistance valveunit. |141). The stop valve device y comprises a cylinder |16 having diametrcally opposite ports |11 and |18, which normally comnection of the stopvalve device |132) leads to the branch |31 la; the endvconnectionofthe stop valve device |152ais Yfed from the branch |1012; and the end connectionwof the stop valve device |13a is fed yfrornthefbranch |1|b. d y

lThe resistance valve unit |14b, shown in Figure '1, hasa'pairv of non-return valves, which are indicatedi-abl' |83, these being connected in parallel butinI opposite directions between the external connections |84 and |85 of the unit. The valve |82-is urged on to itsseatingr by a relatively strong coiled compression springv |85 so as to allow pressure liquid to iiow from the connection. |84 to the connection |85 only after a substantial pressure has been built 4up sufficient to overcome the force of the spring |88. On the other hand the spring |81 by which the valve |83 is closed, is relatively Weak sothat the valve |83 offers practically no resistance; tor the flow of liquid in the opposite direction, normally from the connection |85 to the connection |84. The port |11 is, of course, fed from the branch |10b, while the connection |85 leads to the valve device 88h, the other units |14a, |.15a,. and |15b being correspondingly arranged. i

A pump B fed from a reservoir C is arranged to feed liquid under pressure to any one of the pipe lines 43, 44, 45a and 45h, the remaining three of said pipe lines being in communication with the reservoir C. This eiect may be obtained by means of a valve which is `shown diagrammatically and comprises a hollow cylindrical casing |98, the wall of the latter `being provided with four equidistantly spaced ports connected respectively with the pipe lines 43, 44, 45a and 45D.Y

The interior of the casing is connected with the reservoir C by a pipe 9|. The casing contains a rotatable valve member |92 the interior of which is in permanent communication with the delivery of the pump B by a pipe |93 and is arranged to :f

divert said delivery to any one of the pipe lines 43, 44, 45a, and 4517, depending upon the position to which the valve member 92 is turned.

It will be seen that with the Aparts in the positions shown in Figure 6, the rocker member Bb is holding the valve 61h open. If pressure liquid is fed to the auxiliary pipe line 45h itbuilds up pressure in the branches |18b and |1lb, owing to the action of the resistance units |14b and |15b, which pressure is communicated to the stop valve devices |12a and |13a so that they obstruct both of the branches |10a and |1|a. When the liquid pressure in the branch |1|b has reached a predetermined value it llows through the resistance unit |15b, the valve (i'lbv and the cut-off valve device 14, said pressure liquid then flowing into the cylinder 52 and urging the piston 53 towards the left, the liquid expelled from the cylinder passing back to the reservoir C by Way of the main pipe line 43. When the piston 53reaches the position 53h the rocker member Bb becomes centralised, thus closing the valve 61h and stopping the further supply of pressure liquid. During operation in this manner the stop valves |12a kand |13a have, of course, prevented the pressure liquid from the auxiliary pipe line 45h from opening the valve 61a and thence flowing through the branches |1|a and |10a through the open valve 65a to the left-hand end ofthe cylinder 52. The provision of the resistance valve units |14a, |1511, |14b and |15b ensure that the appropriate stop valves are operated before pressure liquid is fed to the motor unit. To summarise, therefore, pressure liquid fed to the main pipe line 43 moves the motor piston to the extreme right-hand end of its stroke; pressure liquid fed to the auxiliary pipe line 45a, moves the piston to the position 53a; pressure Yliquid fed to the auxiliary Apipe line 45h moves the piston to .the second intermediate position 53h;V and pressure liquid fed to the main pipe line 44`moves the piston to the extreme leithand end of its stroke.

It .will be appreciated' that the constructions whichhave been described are given merely by way of example and that the improved form of control valve device and motor cylinder unit may be used independently if desired; thus any form.

of control' or selector valve device capable of admitting pressure uid to any one of the three pipe lines may be used to bring about the actuation of' the improved motor cylinder unit, while it will be understood that the arrangement of the control valve device whereby the pipe Alines are placed in communication with the reservoir after a predetermined period may be adopted in various forms of liquid pressure remote control system. Y i

Further, the operating means for the timecontrolled valve may be arranged to maintain said valve in its on`position when the piston of the motor cylinder unit is to be held in ,one or each of its two end positions', the lobes of the operating `cam conveniently being extended circumferentially for this purpose. Thus, for some change-speed gear boxes it is necessary to maintain pressure on thek selector lever to keep the latter in its reversefposition, and this can readily be effected by circumferentially extending the lobe I0 of the camA 22' in a direction away from the neutral, position,` the cam then being substantially of the shape shown in Figure 8 where the extension of the lobe Ii is indicated at ||0a.

What I claim is:

1. A motor unit for a fluid-pressure control system, including a block-likeunit formed with a closed cylinder, a piston memberoperative in the cylinder and dividing the same into two working chambers, the block unit being formed with a conduit opening'into one end' of' the cylinder andl with a second conduit openinginto the opposite end of the cylinder, valves mounted in the block unit'and respectively controlling conduits leading intojthe respective ends of the cylinder, distributing valve means for selectively directing the pressure iiuid into either end of the cylinder through the conduits or to both valves to admit pressurev oW through the valve-controlled c'onduits, means operated in the movement ofw the piston member for selectively opening l either` valve in` accordance .withpiston member movement, a sourceof fluid" under pressure, a ti'miiig valve, Ameans biasing` said Vtiming valve to closed position, means ,connecting the source of.' fluid under pressurevwith the inlet ofthetiming valve, means connecting the outlet Iof the timing valve with the inlet ofthe distributing",valve' 1means, manually operated means forbiasin'g the' timing valve to open position to establish connection between the source of fluid' underpress'urej and the distributing valve means, and dampingmeans acting on said timing valve' toi'nterposej a" time lag intermediate the'manual openingthereof and the'return-to-normalclosed position; ,Y

2. A motor unit' for a fluid pressure .control system, including a block` unit `formed with a closed cylinder, said' block beingf formed with independent service conduits Openingt'o the respective ends of the cylinder, said blockb'eing also formed with auxiliary service conduits respecf valve, means biasing said timing valve to closed position, means connecting the source of fluid under pressure with the inlet of the timing valve, means connecting the outlet of the timing valve with the inlet of the manually operated directingv means, manually operated means for biasing the timing valve to open position to establish connection between the source of fluid under pressure and the manually operated directing means, and damping means acting on said timing valve to interpose a time lagintermediate the manual opening thereof and the return to normal closed position.

3. In a liquid pressure remote control system, a motor unit including a cylinder and g member mounted in said cylinder for reciprocation and serving to divide the cylinder into two working spaces, means for independently directing admission of pressure fluid to the respective ends of the cylinder, means for simultaneously directing` pressure uid to an inlet common to independent oW paths to the `respective ends ofthe cylinder, manually operable means for admitting fluid pressure to the cylinder and selectively directing such admission to either of the independent admission means or to the inlet common to said flow paths,

and a valve controlling each flow path with respect to the inlet, said valves being selectiveli7 controlled by and in the movement of the member, a source of fluid under pressure, a timing valve, means normally biasing said timing valve to closed position, a conduit connecting the source of fluid under pressure with the inlet Vof the timing valve, a conduit connecting the outlet of the timing valve with the manually operable means for admitting fluid pressure to the cylinder, said manually operable means including means for opening said timing valve, and damping means for interposing a time lag'intermediate the opening of said timing valve and the return thereof to closed position. v

4. In a liquid pressure remote control system, a motor unit including a cylinder and a member mounted in said cylinder for reciprocation and serving to divide the cylinder into two working spaces, a source of uid under pressure, means for independently directing admission of pressure iluid to the respective ends of the cylinder, means for simultaneously directing pressure fluid to an inlet common to independent iiow paths to the respective ends of the cylinder, manually operable means for admitting fluid pressure to the cylinder and selectively directing such admission to either of the independent admission means or to the inlet common to said flow paths, said manually operable means including directing means for such admitted pressure fluid to either of the independent admission means or to the inlet common to the independent flow paths, a valve controlling each flow path with respect to the inlet,

said valves being selectively controlled by and in the movement of the. member, a timing valve, a"

spring normally biasing said timing valve to closed position, a conduit connecting the inlet of the manually operable means for admitting fluid pressure tothe cylinder with the outlet of the' source of fluid under pressure through said timing valve, means constituting a part of said manually operable means for opening said timing valve against the thrust of said spring, and damping means for interposing a time'lag intermediate the opening of said timing valve and the closure thereof under the bias of said-spring.

5. In a liquid pressure remotecontrol system, a

motor unit comprised of a cylinder anda'member mounted in said cylinder for reciprocation and'` dividing said cylinder into a pair of working to either of a pair of outlets, a control valve dechamber with the control valve device, the piston .I Vin each chamber being arranged to be forced in vice, means connecting the control valve device with the source of uid under, pressure, means connecting thecontrol valve device to the'inlet of the distributing valve, means connecting the outlets of the distributing valve with opposite Working spacesv of the cylinder, means responsive to the direction of movement of the member in said cylinder away from a .predetermined position for opening one or the other of the selective transmitting means in the valve, means defining a chamber in each of the means connecting ythe outlets of the valve with opposite working spaces of the cylinder, a partition piston in eachchamber, a main fluid ypressure line connecting each one direction by pressure fluid supplied through the respective mainline and in the other direc- (tion by fluid pressure supplied through the distributing valve, the resulting movement of the partition piston serving to connect the respective working space of the motor unit with either of the connecting means or line through which fluid is being supplied and to isolate said working space from the other, means for setting the control valve device to selectively supply iluid from the source to one or the other of said main lines or the means connected to the inlet of the distributing valve, and means responsive to operation of said setting means for limiting the time of supply of pressure fluid in the selected direction to a predetermined value.

6. A liquid pressure remote controll system as claimed in claim 5 wherein themeans for limiting 1 the time of supply comprises a piston valve device and wherein a dash-potgoverns the movement of.

control system as 1 

